Electromagnetic device



Oct. 13, 1959 R. D. STAYTON 2,908,735

ELECTROMAGNETIC DEVICE Filed May 19. 1958 2 Sheets-Sheet 1 FIGI.

Oct. 13, 1959 R. D. STAYTON ELECTROMAGNETIC DEVICE 2 Sheets-Sheet 2Filed May 19, 1958 FIGS.

United States Patent fiFice 2,908,785 Patented Oct. 13, 1959ELECTROMAGNETIC DEVICE Robert D. Stayton, St. Louis, Mo., assignor toRickert Electric, Inc., St. Louis, Mo., a corporation of MIS- sour-iApplication May 19, 1958, Serial No. 736,111

6 Claims. (Cl. 200-104) This invention relates to electromagneticdevices, and more particularly to an electromagnetic relay.

Among the several objects of the invention may be noted the provision ofan electromagnetic device, and more particularly a relay, of a typecomprising a frame which constitutes a magnetic core, and alsocomprising an armature and a coil, wherein the frame or core provides aclosed magnetic circuit surrounding the coil for maximum electromagneticefiiciency, and which is of relatively simple and inexpensiveconstruction; and the provision of a device of this character which isof such construction as to minimize the retarding etfect' on thearmature of any residual magnetism which may remain in the core andarmature upon deenergization of the coil so that movement of thearmature upon deenergization of the.

coil is not impeded. Other objects and features will be in part apparentand in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which one of various possibleembodiments of the invention is illustrated,

Fig. 1 is a plan view of a relay of this invention;

Fig. 2 is a side elevation of Fig. 1;

Fig. 3 is a right end elevation of Fig. 2;

Fig. 4 is a left end elevation ofFig. 2;

Fig. 5 is a section taken on line 55 of Fig. 4;

Fig. 6 is a perspective view of the core per se of the relay in a tiltedposition for best illustration; and,

Fig. 7 is a perspective view of the armature per se of the relay in atilted position corresponding to Fig. 6.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring to the drawings, a relay made in accordance with thisinvention is shown to comprise a magnetic frame or core 1, a magneticarmature 3, an electromagnetic coil 5 and a set of contacts 7. The frameor core 1 is of special construction to provide a completely closedmagnetic circuit around the coil 5 for maximum electromagneticefficiency. This construction and the construction of the armature 3 arealso such as to minimize the retarding effect on the armature of anyresidual magnetism Which may remain in the core and armature upondeenergization of the coil, so that quick-opening of the contacts upondeenergization of the coil is assured.

The core 1 (illustrated per se in Fig. 6) is essentially of openrectangular form, two opposite sides of the core constituting first andsecond core legs 9 and 11, the other two sides constituting first andsecond core yokes 13 and 15. The first leg 9 has a central slot 17 (seeFigs. 4 and 6) and the first yoke 13 has a central slot 19 (see Figs. 5and 6), these slots meeting at the corner 21 of the core where the firstleg 9 and first yoke 13 meet. The coil 5 is secured to the second coreleg 11 within the core and extends from the second leg 11 toward theslot 17 in the first leg 9. The armature 3 (illustrated per se in Fig.7) has first and second arms 23 and 25 generally at right angles to oneanother, the Width thereof being slightly less than the Width of slots17 and 19. The armature is mounted for swinging movement on a transverseaxis at the juncture of its arms 23 and 25 and at the corner 21 of thecore, with the first arm 23 extending in the slot 17 and having an endportion opposed to the end of the coil, and with the second arm 25extending in the slot 19. Arm 25 is longer than arm 23 and projectsbeyond the core leg 11.

More particularly, the core 1 is of two-piece construction, one piecebeing designated 27 and the other 29. These pieces, as well as thearmature, are sheet metal stampings made from magnetizable sheet metalsuch as soft steel. The first piece 27 is formed to have a rectangularbase plate portion 31 having holes 33 therein for receiving fastenerssuch as screws (not shown) for attaching the relay to a support (notshown). Bent to extend at right angles from one edge 35 of therectangular base plate portion 31 are two laterally spaced-apart members37 which constitute the first leg 9 of the core 1 and between which isthe slot 17. Bent to extend at right angies from the ends of the legmembers 37 are laterally spaced-apart first yoke members 39 betweenwhich is the slot 19. Extending centrally from edge 35 of the base plateportion 31 coplanar with the latter is a tongue which constitutes thesecond yoke 15 of the core. This tongue 15 is obtained from the portionof the sheet metal blank from which the first core piece 27 is formedoriginally lying between the two members 37 and the two members 39.Tongue 15 has a hole 41.

The second piece 29 is of L-shape, having a fiat rectangular portionwhich constitutes the second leg 11 of the core, and laterallyspaced-apart yoke members 43 bent to extend at right angles from oneedge 45 of leg 11. The width of leg 11 corresponds to the overall widthof leg 9. The width and spacing of yoke members 43 corresponds to thewidth and spacing of yoke members 39. Members 43 are formed with offsetend portions 47. Projecting from the edge 49 of leg 11 opposite its edge45 is a central tang 51 which is received in hole 41 in tongue 15.

The armature 3 is formed with laterally projecting pivots 53 at thejuncture of its arms 23 and 25, and with cutouts 55 at the sides of arm25 adjacent the pivots. The pivots are located within the corner 21 ofthe core and are retained therein by the offset end portions 47 of yokemembers 43, the latter being applied to the inside of members 39 andsecured thereto by bolts 57. These bolts pass through bolt holes inmembers 39 and 41 and also serve to secure in place on the outside ofmembers 39 the contact assembly 7. As shown, this contact assemblycomprises three sets of three spring arms each, the arms of the firstset being designated 59, the arms of the second and intermediate setbeing designated 61, and the arms of the third set being designated 63.These arms are clamped by the bolts 57 between insulation plates 64 andproject out beyond the leg 11 of the core. The intermediate arms 61 arelonger than and project beyond the other arms 59 and 63. Contacts suchas indicated at 65 are provided adjacent the free ends of the arms. Arm25 of the armature has an insulation plate 67 at its free end engagingthe free ends of the intermediate spring arms 61.

Leads for the coil 5 are indicated at 69. The coil is shown as wound ona core 71 having one end riveted as indicated at 73 in a hole '75 in leg11. When the coil is deenergized, the inherent spring bias of arms 61holds the armature in the retracted position in which it is shown inFigs. 2 and 4, the contacts on arm 61 being in engagement with thecontacts on arms 59 and clear of the contacts on arms 63. The retractedposi tion of the armature is determined by the engagement of armaturearm 25 with the bottom of a notch 77 in edge 3 45 of the core leg 11.When the coil is energized, the armature is swung counterclockwise asviewed in Fig. 2 to bring the contacts on arms 61 into engagement withthe contacts on arms -.63 and clear of the contacts on arms 59. The coreconstituted by the first leg members ,37, the first yoke members 39 and43, the second leg member 11 and the second yoke member or tongue 15completely surrounds the coil for maximum electromagnetic efficiency.The cutouts 55 at the sides of annature arm 25 provide arm 25 with aconstricted portion 79 thereby minimizing the tendency of any residualmag netism in the core and armature (which may remain .therein upondeenergization of the coil) to make the armature hang up in itsoperative position and delay its opening. Thus, quick retraction of thearmature upon deenergization of the coil is assured.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. An electromagnetic device comprising a core of open rectangular formmade of magnetizable sheet metal, two opposite sides of the coreconstituting first and second core legs and the other two sidesconstituting first and second core yokes, the first leg and the firstyoke each comprising two laterally spaced-apart members, anelectromagnetic coil within the core, an armature made of magnetizablesheet metal having first and second arms generally at right angles toone another, said armature being pivotally mounted for swinging movementon a transverse axis at the juncture of said arms and at the corner ofthe core where the first leg and first yoke meet, the first armextending between the spaced-apart first leg members and having an endportion opposed to the end of the coil, and the second arm extendingbetween the spaced-apart first yoke members, said core being a two-piececore, the first piece comprising a base plate portion, two laterallyspaced-apart members extending generally at right angles to the baseplate portion at one edge of the latter and constituting the saidspaced-apart first leg members, two laterally spacedapart membersextending generally at right angles to said spaced-apart first legmembers from the ends of the latter and constituting first yoke members,and a tongue extending centrally from said edge .of the base plateportion generally coplanar with the base plate portion and constitutingthe second yoke, the second piece comprising a flat plate portionconstituting the said second leg of the core, and two laterallyspaced-apart additional first yoke members extending generally at rightangles to-said second leg at one edge of the latter and secured to thespaced-apart first yoke members of the first piece. 2, Anelectromagnetic device as set forth in claim 1 wherein the spaced-apartfirst yoke members of the second piece extend on the inside of thespaced-apart first yoke members of the first piece, and the armature ispivotally mounted by means of laterally projecting pivots at thejuncture of its arms, these pivots being confined within said corner ofthe core by offset end portions of said spaced-apart first yoke membersof the second piece.

3. An electromagnetic device as set forth in claim 2 wherein said secondleg is connected to said tongue.

4. An electromagnetic relay comprising a core of open rectangular formmade of magnetizable sheet metal, two opposite sides of the coreconstituting first and sec ond core legs and the other two sidesconstituting first and second core yokes, the first leg and the firstyoke each comprising two later-ally spacedapart members, anelectromagnetic coil secured to the second leg within the core andextending toward the first leg, an armature made of magnetizable sheetmetal having first and second arms generally at right angles to oneanother, said armature being pivotally mounted for swinging movement ona transverse axis at the juncture of said arms and at the corner of thecore where the first leg and first yoke meet, the first arm extendingbetween the spacedapart first leg members and having an end portionopposed to the end of the coil, and the second arm extending between thespaced-apart first yoke members and projecting beyond said second leg,and a set of contacts mounted on the core, and means at the end of saidsecond arm engageable with said set of contacts, said cor-e being atwo-piece core, the first piece comprising a flat base plate portion,two laterally spaced-apart members extending generally at right anglesto the base plate portion at one edge of the latter and constituting thesaid spaced-apart first leg members, two laterally spaced-apart membersextending generally at right angles to said spaced-apart first legmembers from the ends of the latter and constituting first yoke members,and a tongue extending centrally from said edge of the base plate portion generally coplanar with the base plate portion and constituting thesecond yoke, the second piece comprising a fiat rectangular plateportion constituting 'the said second leg of the core, and two laterallyspaced-apart additional first yoke members extending generally at rightangles to said second leg at one edge of the latter and secured to thespaced-apart first yoke members of the first piece by means alsosecuring the set of contacts to the core.

5. An electromagnetic relay as set forth in claim 4 wherein thespaced-apart first yoke members of the second piece extend on the insideof the spaced-apart first yoke members of the first piece, and thearmature is pivotally mounted by means of laterally projecting pivots atthe juncture of its arms, these pivots being confined within said cornerof the core by ofiset end portions of said spaced-apart first yokemembers of the second piece.

6. An electromagnetic relay as set forth in claim 5 wherein the secondleg has a tang at the edge thereof opposite its said one edge receivedin a hole in said tongue.

References Cited in the file of this patent UNITED STATES PATENTS1,114,225 Cahusac Oct. 20, 1914 1,904,847 Babbitt Apr. 18, 19332,339,610 Baker Jan. 18, 1944 2,790,045 Roesen Apr. 23, 1957

